How to do the thinking questions on page 28 of the sixth grade math book in primary school? How to do the thinking questions on page 28 of the sixth grade math book in primary school? The steel around turned into water, water. Let the height of round steel be h cm and the radius of barrel be r cm.

Put a section of round steel with a radius of 5 cm into the water, and the water level will rise by 9 cm.

This shows that the volume of the whole round steel is the same as that when the water level of the bucket rises by 9 cm.

You can get the equation.

5*5*π*h=r*r*π*9

That is, there is an equation-25h = 9R2 (the square of R).

After the round steel is vertically pulled out of the water by 8 cm, the water level drops by 4 cm.

This shows that the volume of round steel immersed in water at this time is

5*5*π*(h-8)

At this time, the water level of the bucket rose by 9-4=5 cm.

free

5*5*π*(h-8)=5*π*r*r

That is, Equation 2, 25h-200 = 5R2.

One and two simultaneous cubic equations can be solved.

H= 18 (cm)

At this time, the volume of round steel is

V = 5 * 5 *18 * π = 450 π ≈1413 (cubic centimeter)